‘When in Vietnam, do as the Vietnamese do’ comes to mind, as Obama sits down for a $6 meal at a streetside restaurant in Hanoi, hours after lifting an historic arms embargo with the former enemy of the US.

On Monday night the US president perched on a blue plastic stool opposite Anthony Bourdain, a celebrity chef and food critic who fronts a travel show about hidden culinary gems around the world.

US Secret Service and local police closed down the streets surrounding the restaurant on Monday evening, while the pair ate Vietnam’s famed “bun cha” delicacy.

While 54-year-old restaurant owner Nguyen Thi Lien knew a foreign television crew was on the way, she had no idea who was turning up.

“His presence in our restaurant was a great surprise for my whole family, who could never have imagined it, even in our dreams,” she told AFP on Tuesday.

The event was widely followed on social media, with users all over the world weighing in on his appearance, walking the same streets as ordinary citizens of Vietnam.

A photo posted by anthonybourdain (@anthonybourdain) on May 23, 2016 at 7:22am PDT

Chef Anthony Bourdain described Obama’s chopstick skills as “on point” in an Instagram post that has since been liked over 130,000 times.

Users were quick to notice that no one in the hole-in-the-wall restaurant seems aware that the most powerful man in the world was in their local spot. “How are the people around just so chill??” asked one.

Outside, the crowd was more aware of his presence, and a throng of people gathered to get a glimpse.

One Instagram user noted that the President’s restaurant etiquette wasn’t up to Vietnamese standards: “his elbow shouldn’t be on the table?“ she said.

Pictured sipping a beer, users wanted to know what he was drinking “So what is the President’s beer of choice @anthonybourdain ? Bia Hanoi? Biere Larue?”

Turns out it was the former: Bia Han oi according to another user.

A strange observation by many on Twitter was that there appears to be chopsticks on the floor, despite his supposed chopstick skills. “Is it just me or does anyone not realise how a red chopstick wrapper has been dropped on the floor?”.

Another was more positive: “Proud of the president, that he placed his chopsticks neatly on top of his bowl and not stabbed them into the noodles – that would have been so rude and a big sign of disrespect”.

Bourdain is a known fan of Vietnamese street food, and visited the country often throughout the course of his long-running show, No Reservations. According to a tweet, the $6 meal was his treat.